3mm Testing in July 2001

15
3mm Testing in July 2001 Tony Wong ATNF Epping CA Forum, 6 Sep

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3mm Testing in July 2001. Tony Wong ATNF Epping CA Forum, 6 Sep. Bandpass at 90.56 GHz. 3c279 128 MHz 64 chans. Bandpass at 90.68 GHz. 3c279 128 MHz 64 chans. Bandpass at 90.68 GHz. After bandpass calibration applied. Phase/amp stability at 90 GHz.  RMS  10  - PowerPoint PPT Presentation

Transcript of 3mm Testing in July 2001

Page 1: 3mm Testing in July 2001

3mm Testing in July 2001

Tony Wong

ATNF Epping

CA Forum, 6 Sep

Page 2: 3mm Testing in July 2001

Bandpass at 90.56 GHz

3c279128 MHz64 chans

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3c279128 MHz64 chans

Bandpass at 90.68 GHz

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After bandpass

calibration applied

Bandpass at 90.68 GHz

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Phase/amp stability at 90 GHz

RMS 10but

amplitude variations

much greater!

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Phase/amp stability at 90 GHz

Phase cycles

every 20 minutes

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Phase/amp stability at 22 GHz

Amps decreasing- worsening weather?

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How often to calibrate?

5 min on 3c279:

10% amp fluctuation, RMS 15

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System Temperatures

Tsys, corrected for atmospheric absorption, was determined using

the paddle while stepping in frequency from 84-87

GHz.Some of the frequency variation may be due to

varying atmosphere.

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System Temperatures

Same observation for 87-91 GHz.

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System Temperatures

Since the “psJy” scale is derived

assuming constant GTsys of 500 Jy, the

visibility amplitude in psJy is anticorrelated

with Tsys.

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Sensitivity Estimate, 86 GHz

Assuming a flux of 8 Jy for Uranus, the observed amplitude and Tsys give the geometric mean Jy/K for the two antennas.

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Sensitivity Estimate, 90 GHz

Note strong RFI at 88.160 GHz. Significant RFI is also found at 88.000 and 88.320 GHz, weaker at 88.240 GHz.

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Some Science ResultsMolecules in IRC+10216

HCN

HNC

C3N

SiS

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Some Science ResultsDense Gas in the LMC

HCN

HCO+

Thermal SiO in N6334

W 17.5”

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